Decades of expertise in portable octane, cetane and bio-fuel with lab-accurate analysis. 45 State Agencies have used Zeltex portable fuel octane analyzers over the years, making the ZX-101 series the gold standard in portable fuel testing. The main way that fuel is analyzed is through a CFR engine, which takes time, costs a lot of money, and destroys the sample. Our portable fuel octane analyzers are quick, preserve the sample, and the results are very close to the CFR engines. Now the ZX-101SQ makes it even easier and more reliable to analyze fuel samples where you need it most, when you need it most.